Growers have much to consider as Mid-South corn harvest nears

When considering the Mid-South corn harvest, one of Dennis Gardisser's first concerns is how quickly and efficiently the grain can be handled. Potential bottlenecks abound, says the Arkansas Extension engineer.

“I'm afraid we'll be able to harvest it a lot quicker than we can get rid of it,” he says. “One issue is having enough trucks and buggies to keep the harvest flow even. We don't want the harvest to be throttled by an inability to get the grain out of the combine. I hope everyone has that planned out, whether using on-farm storage or another option.

He says managing the speed of harvest will be critical. “Many new corn farmers don't realize how quickly corn comes out of the field. If you've got 200 bushels per acre, the grain piles up quickly. Everyone will be at the barn trying to unload at the same time, I'm afraid.”

“It may sound simplistic, but everyone needs to remember the combine should be set a bit differently for corn than for rice. The combine needs a corn header, if at all possible. We have seen situations where farmers have tried to cut corn with a flat-table header. But that's very difficult to do — harder on the combine, harder to keep grain loss minimized, and it's slower.”

Anyone new to corn headers needs to “study set-up recommendations. The headers aren't hard to set. But if they're not working properly, the efficiency and grain losses can drop dramatically.”

Coming right up

Arkansas' corn harvest isn't far off, says Jason Kelley. “In southeast Arkansas — Eudora, Chicot County, Ashley County — where the corn wasn't burned back by the Easter freeze, there will be some corn harvested in July,” says the Arkansas Extension corn specialist. “But most of our corn harvest will kick off in early August. At least that's what I'm hoping for — that would give us a little more time to prepare.”

The harvest in Louisiana could begin sooner, says David Lanclos, LSU AgCenter corn specialist, because of the drought conditions that have persisted in some areas. “There's plenty of speculation combines could be running as early as July 15,” he said. “Although those situations may be isolated, I don't doubt it could happen.”

Drought stress might also mean Mississippi could be looking at a big crop maturing in a relatively short time, according to Erick Larson, Extension corn specialist at Mississippi State University. “Drought stress may accelerate the maturity process and harvest may not be spread out as much as it normally is, depending on rainfall.”

Lack of irrigation in west Tennessee's production area is also causing yield loss and could bring on harvest faster than expected, said Angela Thompson, Tennessee Extension corn specialist.

Most of the specialists say areas hit by the Easter freeze and subsequent replanting will definitely mean a prolonged harvest.

“In other states, if things go as expected, the corn can come off at nearly the same time,” says Kelley. “Here, we've got a bunch of replanted corn — corn that, in a normal year, would be considered late-planted in late April and into May.

“In the beginning our producers might have thought, ‘We'll get the corn off and out of the way before harvesting rice or other crops.’ Now, though, this replant corn will probably throw a kink into those plans. It's much more likely for our corn harvest to have a conflict.”

Moisture levels

Based on past data, the best harvest moisture is between 18 percent and 22 percent. Corn can be allowed to dry more in the field. But doing that can lead to losses — how much largely depends on the variety.

Regardless, Gardisser says harvest should begin around the 20 percent moisture level. “With that in mind, there has to be a way to dry it. If they let it stand in the field, the risk is wind blowing the crop over and extra losses during picking.”

Unfortunately, irrigation water won't cover a field equally. Drier areas often include corners, sandy soils, and high spots. “The problem is anytime corn is stressed the potential for aflatoxin goes up. So if there are any suspect spots in the field — corners, ends, whatever — pick them separately, perhaps last. Doing that means less chance of combine of equipment being contaminated by any aflatoxin that may be present.”

It doesn't take much aflatoxin to ruin someone's day, warns Gardisser. “And if a crop is infected with aflatoxin, it can't be used for cattle feed nor for ethanol. I've heard, ‘Well, if it's infected, I'll just send it off to produce ethanol.’ But the renewable fuel industry won't take it either.”

In fact, the crop can't even cross state lines with aflatoxin at more than 25 parts per million.

Also, avoid letting corn sit in a hopper belly or truck bottom for more than 12 hours. “The first load of the morning is often the dampest. Dew is on the crop when it is combined and it goes right to the hopper belly bottom. It sits there until the truck is full and then it may sit at the elevator for a few more hours. In that situation, the potential for the growth of unwelcome disease increases.”

On-farm storage and drying of corn doesn't have to involve corn-centric equipment. Unless the corn is very wet, “standard rice bins do a fine job in most cases.”

Not drying corn could produce a stiff penalty. Anyone not doing so, “will be sorry when they take high-moisture corn to the elevator. I'd try to get the moisture down somehow.”

The optimum moisture content for corn is 15.5 percent. To reach that percentage, how much does corn shrinkage matter? “I've heard things said like ‘Well, corn weighs more when I sell it at 18 percent moisture. That should override any dockage.’ But, no, I guarantee that isn't the case. The dockage cost is much more than the 2 or 3 extra pounds of water moisture. The farmer won't win in that game.”

Regardless, 15.5 percent moisture is prime. And farmers don't want to get below that percentage because “there's no premium for moistures below 15.5. That's another way farmers can lose money.”

In storage, Gardisser likes to keep corn at 14 percent moisture or below. “Put some air on it, get it dried.” Farmers make a mistake when binned corn is subjected to both heat and fans. “The thought is adding heat will speed the drying process up. So they may set the air at 9 percent equilibrium and they're wasting money.

“The best thing to do is get a psychrometer and measure the air quality. If the corn is going to market, turn the fans on and get the moisture to 15.5 percent. Then quit.”

Easing the crunch

Farmers looking to ease a storage crunch frequently ask Gardisser about the large, in-field storage bags often used outside the United States.

“These bags must be sealed — no air. If the bag is breached, the grain can turn to mush. Whatever happens, at this point we have no data to dispute — good, bad or indifferent — the claims about how these bags work. But since our storage capacity is limited, a bunch of those bags will be utilized.

“I suspect the mistakes with these bags will come where there's not a good seal or deer or rodents find it.”

Data on the storage bags out of Israel and South America “looks fine. But no one — and I've asked some knowledgeable people about this — including the companies selling the bags, has data on what happens to corn in these bags in our temperature and humidity environment. That data doesn't exist. We'll have it next year.”

There have also been queries about spiked-tooth combines. “We recommend against using that, if possible. It breaks the cob into pieces and puts a lot of material into the hopper and it's harder to separate. We also recommend against using flat-table cutters.”

The header needs to be on the same spacing as the planter. “We don't want a 36-inch row and a 30-inch header.”

New corn producers also need to know that corn headers are large and heavy. “Many times a corn header is added to a combine and they have to add weight to the back end. That keeps the back end down so they can steer when there's not a lot in the hopper. Two-wheel drive combines are especially prone to being tipsy with a corn header on.”

Other issues

Gardisser believes elevators will be “very critical on the quality of corn they'll take. They may not want high-moisture corn because that'll slow them down too — and energy costs are high. So they'll be selective and I think, in some cases, farmers will have a hard time finding a place to take their corn.”

Depending on the weather, if there are any suspicions of aflatoxin “they'll also be extremely selective. They don't want to contaminate a whole barge with one mistake. And that's fine.

“What all this means is farmers need to be speaking with their elevators and have a good, clear understanding in writing about the elevators' parameters in taking corn.”